1. Field of the Invention
The present invention relates to an ophthalmic surgery apparatus which treats by irradiating a laser beam to an eye of a patient, and more particularly to a mechanism for delivering the laser beam to a desired position of the eye and for tracking movement of the eye.
2. Description of the Related Art
As an ophthalmic surgery apparatus which treats by irradiating a laser beam to an eye of a patient, for example, a corneal surgery apparatus which uses an excimer laser beam is known. This apparatus ablates a surface of a cornea by irradiating the excimer laser beam so as to remove a diseased portion of the cornea and corrects an ametropia by changing a curvature of the cornea.
In the case that this apparatus is used, an operator makes the patient fix a fixation target with the eye, then aligns an irradiating optical system with the eye so as to be desired condition with observing an alignment target. The alignment is completed, then the operator makes this apparatus irradiate the laser beam so as to ablate determined amount of a desired area of the eye.
Though the patient is made to fix the fixation target with the eye, if an eyeball of the eye happens to move during the alignment or the laser beam irradiation and the movement is confirmed by the operator, then the operator must do the alignment over again once more from beginning, or the operator must discontinue the laser beam irradiation and do the alignment over again.
As described above, doing the alignment over again is a burden to both the patient and the operator because of taking much a long time for its operation or the like. Furthermore, in the case that the eyeball moves often, the burden is much more.
And if the operator does not notice the movement of the eyeball and continues the laser beam irradiation, then the cornea is not ablated so as to be an expected shape, therefore a refractive power of the eye after the operation is influenced thereby.
Furthermore, if the operator is not accustomed to operating the apparatus, then the alignment itself takes much time.
The present invention has been made in view of the above circumstances and has an object to overcome the above problems, and to provide an ophthalmic surgery apparatus, which may make it easy to align a laser beam irradiating optical system with an eye of a patient without burdening both a patient and an operator.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, an ophthalmic surgery apparatus comprising an observation optical system for observing an anterior portion of an eye of a patient, and a laser beam irradiating optical system for irradiating a laser beam for treatment to the eye, the ophthalmic surgery apparatus is a corneal surgery apparatus irradiating the laser beam to a cornea of the eye and ablating a surface of the cornea, the apparatus comprises a moving means for moving the laser beam irradiating optical system relatively against the eye, an illuminating means for illuminating a large area of the anterior portion of the eye, a photoelectric transducing means having a two-dimensional light sensing plane, for sensing distribution of light volume of the anterior portion of the eye illuminated by the illuminating means, a pupil position sensing means for sensing the position of a pupil by processing the signal transmitted by the photoelectric transducing means, a control means for controlling the moving means based on results sensed by the pupil position sensing means, a tracking signal generating means for generating a signal to track movement of the eye, whereby the moving means is controlled by the control means so as to track movement of the eye by inputting a signal generated by the tracking signal generating means, and an irradiation prohibiting means for prohibiting irradiation of the laser beam in the case that the position of the pupil misses the predetermined limits.
In another aspect of the present invention, an ophthalmic surgery apparatus comprising an observation optical system for observing an anterior portion of an eye of a patient, and a laser beam irradiating optical system for irradiating a laser beam for treatment to the eye, the ophthalmic surgery apparatus is a corneal surgery apparatus irradiating the laser beam to a cornea of the eye and ablating a surface of the cornea, the apparatus comprises a moving means for moving the laser beam irradiating optical system relatively against the eye, an illuminating means for illuminating a large area of the anterior portion of the eye, a photoelectric transducing means having a two-dimensional light sensing plane, for sensing distribution of light volume of the anterior portion of the eye illuminated by the illuminating means, a pupil position sensing means for dividing a sensing area of the photoelectric transducing means into the predetermined number, then sensing the position of a pupil based on analysis and comparison for light-and-shade information of the divided respective areas, a pupil position sensing means divides the two-dimensional sensing plane into at least more than four members, then senses the position of a pupil based on bias of the light-and-shade which is obtained every divided area, and a control means for controlling the moving means based on results sensed by the pupil position sensing means.
In another aspect of the present invention, an ophthalmic surgery apparatus comprising an observation optical system for observing an anterior portion of an eye of a patient, and a laser beam irradiating optical system for irradiating a laser beam for treatment to the eye, the ophthalmic surgery apparatus is a corneal surgery apparatus irradiating the laser beam to a cornea of the eye and ablating a surface of the cornea, the apparatus comprises a moving means for moving the laser beam irradiating optical system relatively against the eye, an illuminating means for illuminating a large area of the anterior portion of the eye, a photoelectric transducing means having a two-dimensional light sensing plane, for sensing distribution of light volume of the anterior portion of the eye illuminated by the illuminating means, a pupil position sensing means for dividing a sensing area of the photoelectric transducing means into the predetermined number, then sensing the position of a pupil based on analysis and comparison for light-and-shade information of the divided respective areas, a pupil position sensing means including a light-and-shade sensing means for dividing the two-dimensional light sensing plane into some number which have areas not adjacent each other, then obtaining the light-and-shade information every the divided area, a judging means for judging whether there is difference of the predetermined light-and-shade degree in the light-and-shade information of areas not adjacent each other and a pupil position specifying means for specifying that the pupil exists in dark side area in the case that the judging means judges that there is the difference of the predetermined light-and-shade degree and a control means for controlling the moving means based on results sensed by the pupil position sensing means.
Further, in another aspect of the present invention, an ophthalmic surgery apparatus further comprises a threshold level determining means for determining a threshold level for use in specifying a pupil area, and wherein the pupil position sensing means senses the position of the pupil based on the threshold level determined by the threshold level determining means and the signal of distribution of light volume transmitted by the photoelectric transducing means.
According to the present invention, it is capable of preventing an irradiating area from deviating, and is capable of treating an eye of a patient appropriately, because the apparatus can track the eye even if an eyeball of the eye moves during the laser beam irradiation. Also, a stable tracking can be realized with reducing an effect caused by a noise light.
Furthermore, since the performance for operating is improved, so burden is allowed to be decreased for both the patient and the operator. Furthermore, the trouble of the alignment is allowed to be decreased, therefore the alignment adjustment can be performed easily.